1. Field of the Invention
The present invention generally relates to combustion systems of gas turbine engines. More particularly, this invention relates to a method of fabricating a gas turbine engine combustor dome suitable for use in the development and testing of a combustor.
2. Description of the Related Art
A conventional gas turbine engine of the type for aerospace and industrial applications has a combustor with an annular-shaped combustion chamber defined by inner and outer combustion liners. The upstream ends of the combustion liners are secured to a pair of mounting bands spaced radially from each other on an annular-shaped dome, which defines the upstream end of the combustion chamber. Between the mounting bands, the dome has an annular-shaped wall, typically disposed at some angle (“dome angle”) to a plane perpendicular to the axis shared by the dome and combustion chamber. A number of circumferentially-spaced contoured cups are formed in the dome wall, with each cup defining an opening in which one of a plurality of air/fuel mixers, or swirler assemblies, is individually mounted for introducing a fuel/air mixture into the combustion chamber. The dome is important to the desired performance and functionality of the combustor since the dome affects the shape of the combustion chamber and the size and locations of the openings in the dome locate and affect the performance of the swirler assemblies mounted within the openings. Consequently, domes have been manufactured as a one-piece stamping to provide accuracy and consistency in the location and shape of the dome, including its cups and mounting bands.
During the development of a gas turbine engine, combustor mockups are often fabricated to perform a variety of tests, such as profile and pattern factor development, that assess the performance of a combustor and its individual components, including the aerodynamic, heat transfer and mechanical design requirements of the dome. One approach for fabricating a dome test model for development testing is to fabricate a production-type tool capable of forming the entire dome in a single stamping operation. However, a significant drawback with this approach is the large capital expense and lead times required to fabricate the tooling. Furthermore, this tooling is dedicated to a particular dome design that may be one of a number of designs evaluated before a suitable production design is identified. Another approach is to fabricate a number of individual components, such as cones, cylinder and flat plates, that can be assembled and welded together to form domes of various configurations. However, the suitability of this approach depends on the ability of the fabricator to consistently produce a relatively large number dimensionally accurate parts, which must then be carefully assembled to obtain the relative positions and orientations of the individual dome components.
In view of the above, it would be desirable if an improved method were available for fabricating a dome that is suitable for developmental testing, wherein the dome can be designed and assembled with reduced costs and shorter lead times, yet meet the stringent dimensional requirements to accurately replicate the performance of the dome design being evaluated for production.